With waiting period running into weeks or even months for quite a few car bookings, when is the right time to apply for a car loan considering the high wait time?

I recently enquired about this at a Hyundai showroom and they were quite proactive about applying for a loan immediately even though the waiting period was 2 months for the Hyundai Venue.

I did the same with a Tata showroom and they were least bothered about having any discussion about financing. The waiting period they said for the Nexon was 3 to 4 months.

So to all the folks who booked a car recently and had some waiting period, kindly guide me as to when would be the right time to initiate the car loan application process. Would it make sense that I apply for the loan right away even if waiting period is 2 months or would it make sense to wait for the car being alloted to me?